Influence of Soil–Structure Interaction on the Seismic Performance of Fixed-Base and Flexible-Base RC Buildings of Different Plan Shapes and Heights

Author

D. Bhavani Prasad, Ch. Jayanthi, K. Siva Teja, K. Hemanth

Abstract

 Conventional seismic analysis of reinforced concrete (RC) buildings assumes a rigid, fixed base, which neglects the deformability of the supporting soil. This study examines how soil–structure interaction (SSI) affects the seismic response of RC frame buildings of rectangular, L-shaped and T-shaped plan, with heights of G+3, G+7, G+11 and G+15. Digital models were developed and analysed in STAAD.Pro using the seismic coefficient method and response spectrum analysis in accordance with IS 1893 (Part 1):2016. Soil flexibility was represented by translational and rotational springs at the base and compared against fixed-base models. Storey shear, storey displacement, natural time period, storey drift ratio and storey stiffness were compared across configurations. Flexible-base models showed longer time periods (about 17% higher), considerably larger displacements (about 16% for G+3 rising to about 60% for G+15) and a lower base shear (about 5%) than fixed-base models, with drift ratios and stiffness also affected by SSI; the L-shaped building generally recorded the largest displacements. The effects grew with building height. Life cycle assessment (LCA) and embodied carbon are introduced as sustainability considerations, although no LCA calculations are presented in this study. The results show that fixed-base assumptions may underestimate deformation demands, particularly in tall and plan-irregular RC buildings.

Keywords

soil–structure interaction; RC buildings; plan irregularity; response spectrum analysis; STAAD.Pro; storey drift; life cycle assessment

Full Text:

Download Paper PDF

References

[1] G. R. Rao, J. C. Sunil, and R. Vijaya, “Soil-structure interaction effects on seismic response of open ground storey buildings,” Sadhana, vol. 46, no. 2, p. 105, 2021, doi: 10.1007/s12046-021-01633-0.

[2] M. Tasleem, M. Firoj, and A. Bahuguna, “Effect of open-ground storey on RC frame buildings incorporating soil–structure interaction,” Asian J. Civ. Eng., vol. 23, no. 4, pp. 471–485, 2022, doi: 10.1007/s42107-022-00435-x.

[3] M. Ahmed, M. K. Dad Khan, and M. Wamiq, “Effect of concrete cracking on the lateral response of RCC buildings,” Asian J. Civ. Eng. (Building and Housing), vol. 9, no. 1, pp. 25–34, 2008. [Online]. Available: https://sid.ir/paper/298781/en

[4] Y. Yardimci and Ö. F. Bayraktarlı, “Impact of seismic design requirements on the environmental performance of reinforced concrete buildings: A BIM-integrated comparative LCA,” Buildings, vol. 16, no. 12, p. 2408, 2026, doi: 10.3390/buildings16122408.

[5] S. O. El Janous and A. El Ghoulbzouri, “Seismic vulnerability of irregular reinforced concrete buildings considering the soil-structure interaction,” 2024, doi: 10.5829/ije.2024.37.01a.10.

[6] S. Dhakal and H. Chaulagain, “Seismic behaviour of plan irregular reinforced concrete buildings considering soil effects,” J. Build. Pathol. Rehabil., vol. 8, no. 1, p. 46, 2023, doi: 10.1007/s41024-023-00280-8.

[7] R. Ghosh and R. Debbarma, “Effect of slope angle variation on the structures resting on hilly region considering soil–structure interaction,” Int. J. Adv. Struct. Eng., vol. 11, no. 1, pp. 67–77, 2019, doi: 10.1007/s40091-019-0219-3.

[8] S. K. Prajapati and J. A. Amin, “Seismic assessment of RC frame building designed using gross and cracked section as per Indian standards,” Asian J. Civ. Eng., vol. 20, no. 6, pp. 821–836, 2019, doi: 10.1007/s42107-019-00147-9.

[9] B. R. Jayalekshmi and H. K. Chinmayi, “Effect of soil flexibility on seismic force evaluation of RC framed buildings with shear wall: A comparative study of IS 1893 and Eurocode 8,” J. Struct., vol. 2014, no. 1, Art. no. 493745, 2014, doi: 10.1155/2014/493745.

[10] P. A. H. Pham, N. T. Phat, and N. H. Nguyen, “Stiffness degradation effects on seismic behavior of RC frame structures,” 2026, doi: 10.28991/CEJ-2026-012-02-011.

[11] R. Mai, M. E. Nasr, W. El-Badrawy, and N. E. Nasr, “Effect of infilled frames on reduction factor (R) for RC irregular structure,” Civ. Eng. J., vol. 10, no. 8, 2024, doi: 10.28991/CEJ-2024-010-08-09.

[12] S. Prasanth and G. Ghosh, “Effect of cracked section properties on the resilience based seismic performance evaluation of a building,” in Structures, vol. 34, pp. 1021–1033, Elsevier, Dec. 2021, doi: 10.1016/j.istruc.2021.08.035.

Share your valuable work from Social Media Buttons